Enhanced telephone set on the Inter-IC bus

A microcontroller-based enhanced telephone set designed and developed using the Inter-IC (I/sup 2/C) bus system is described. Besides functioning as a subscriber telephone, this feature phone incorporates a software-controlled ringer function, pulse and DTMF (dual-tone multifrequency) dialing, redial and extended redial features, direct dialing for emergencies, on-chip memory for 10 repertory dial numbers of 18 digits, direct access repertory dialing, and a liquid-crystal display.<
>